Originally Posted by
Ferras
wow u type fast then
I was with my friend and we were talking about sodium potassium pumps and then I was like "Active transport is responsible for cells' containing relatively high concentrations of potassium ions but low concentrations of sodium ions. The mechanism responsible for this is the sodium-potassium pump, which moves these two ions in opposite directions across the plasma membrane. This was investigated by following the passage of radioactively labeled ions across the plasma membrane of certain cells. It was found that the concentrations of sodium and potassium ions on the two sides of the membrane are interdependent, suggesting that the same carrier transports both ions. It is now known that the carrier is an ATP-ase and that it pumps three sodium ions out of the cell for every two potassium ions pumped in.
The sodium-potassium pump was discovered in the 1950s by a Danish scientist, Jens Christian Skou, who was awarded a Nobel Prize in 1997. It marked an important step forward in our understanding of how ions get into and out of cells, and it has a particular significance for excitable cells such as nervous cells, which depend on this pump for responding to stimuli and transmitting impulses. The Na+
/K+
-ATPase helps maintain resting potential, avail transport, and regulate cellular volume.[1] It also functions as signal transducer/integrator to regulate MAPK pathway, ROS, as well as intracellular calcium. In most animal cells, the Na+
/K+
-ATPase is responsible for about 1/5 of the cell's energy expenditure.[citation needed] For neurons, the Na+
/K+
-ATPase can be responsible for up to 2/3 of the cell's energy expenditure.[2]
In order to maintain the cell membrane potential, cells keep a low concentration of sodium ions and high levels of potassium ions within the cell (intracellular). The sodium-potassium pump moves 3 sodium ions out and moves 2 potassium ions in, thus, in total, removing one positive charge carrier from the intracellular space. (Please see Mechanism for details).
The action of the sodium-potassium pump is not the only mechanism responsible for the generation of the resting membrane potential. Also, the selective permeability of the cell's plasma membrane for the different ions plays an important role. All mechanisms involved are explained in the main article on generation of the resting membrane potential.
Export of sodium from the cell provides the driving force for several secondary active transporters membrane transport proteins, which import glucose, amino acids, and other nutrients into the cell by use of the sodium gradient.
Another important task of the Na+
-K+
pump is to provide a Na+
gradient that is used by certain carrier processes. In the gut, for example, sodium is transported out of the reabsorbing cell on the blood (interstitial fluid) side via the Na+
-K+
pump, whereas, on the reabsorbing (lumenal) side, the Na+
-glucose symporter uses the created Na+
gradient as a source of energy to import both Na+
and glucose, which is far more efficient than simple diffusion. Similar processes are located in the renal tubular system."
Cited my sources n everything. This was like 20 seconds ago. Much typing speed.
